OBJECT TRACKING AND STEER MANEUVERS FOR MATERIALS HANDLING VEHICLES

• US 20110166721A1
• Filed: 02/23/2011
• Published: 07/07/2011
• Est. Priority Date: 08/18/2009
• Status: Active Grant

• Current Assignee: Crown Equipment Corporation
• Original Assignee: Crown Equipment Corporation
• Inventors: Schumacher, Mark E., McCroskey, William W., Schloemer, James F., Siefring, Vernon W., Wellman, Timothy A., Castaneda, Anthony T.
• Granted Patent: US 8,731,777 B2
• Time in Patent Office: Days
• US Class Current: 701/2
• CPC Class Codes: B62D 15/0265 Automatic obstacle avoidance by steering
• CPC Class Codes: B62D 6/001 the torque NOT being among the input parameters
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: B66F 9/07568 Steering arrangements
• CPC Class Codes: B66F 9/07581 Remote controls
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 2201/0216 Vehicle for transporting goods in a warehouse, factory or similar
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices

Abstract

A materials handling vehicle automatically implements steer maneuvers when objects enter one or more zones proximate the vehicle, wherein the zones are monitored by a controller associated with the vehicle. The controller tracks objects in the zones via sensor data obtained from at least one obstacle sensor located on the vehicle and via dead reckoning. The objects are tracked by the controller until they are no longer in an environment proximate the vehicle. Different zones result in different steer maneuvers being implemented by the controller.

Claims

1. A method for a materials handling vehicle to automatically perform a steer correction maneuver comprising:

receiving sensor data from at least one sensing device by a controller on a materials handling vehicle;

detecting based on the received sensor data that a first object is located in a first zone defined at least partially on a first side of the vehicle;

detecting based on the received sensor data that a second object is located in a second zone defined at least partially on a second side of the vehicle, wherein the second object is closer to a central axis of the vehicle than the first object; and

automatically performing a steer correction maneuver by steering the vehicle toward the first object so as to steer the vehicle away from the second object until at least one of;

the first object enters a predefined portion of the first zone; and

the second object exits a predefined portion of the second zone.

2. The method of claim 1, wherein the predefined portion of the first zone comprises a portion of the first zone wherein further steering of the vehicle toward the first object is determined to not be permitted.

3. The method of claim 1, wherein the predefined portion of the second zone comprises a portion of the second zone wherein further steering of the vehicle away from the second object is determined to not be required.

4. The method of claim 1, further comprising straightening a heading of the vehicle upon at least one of:

the second object exiting the predefined portion of the second zone; and

the first object entering the predefined portion of the first zone.

5. The method of claim 1, further comprising initiating a braking operation if at least one of the first object and the second object enters a portion of its corresponding zone that comprises a stop zone.

6. The method of claim 1, wherein automatically performing a steer correction maneuver comprises automatically performing the steer correction maneuver while the materials handling vehicle is traveling in response to receiving a wirelessly transmitted travel request by a corresponding wireless transmitter.

7. The method of claim 1, wherein receiving sensor data from at least one sensing device comprises receiving the sensor data from a scanning laser device.

8. The method of claim 1, wherein the first and second zones each comprise:

a stop zone, wherein if an object is detected in the stop zone, the vehicle is caused to initiate a braking operation;

a no steer zone laterally outwardly from the stop zone, wherein if an object is detected in at least a portion of the no steer zone the vehicle is not permitted to turn toward the no steer zone in which the object was detected; and

a steer zone laterally outwardly from the no steer zone, wherein if an object is detected in at least a portion of the steer zone the vehicle is permitted to turn toward the steer zone in which the object was detected.

9. The method of claim 8, wherein the predefined portion of the first zone comprises the no steer zone of the first zone.

10. The method of claim 8, wherein the predefined portion of the second zone comprises the steer zone of the second zone.

11. The method of claim 8, wherein the first and second zones each further comprise a hug zone laterally outwardly from the steer zone, wherein the hug zone is usable by the controller to steer the vehicle relative to selected objects detected in the corresponding hug zone such that the vehicle is substantially maintained at a desired distance from the selected object.

12. A method for tracking objects detected by at least one sensing device on a materials handling vehicle, the method comprising:

receiving sensor data from at least one sensing device by a controller on a materials handling vehicle, wherein the sensor data comprises;

data representative of whether an object is detected in a scanned zone that is scanned by the at least one sensing device, the scanned zone being a part of an environment in which objects are tracked; and

data representative of a lateral distance that any detected objects are from a reference coordinate associated with the vehicle;

wherein each detected object is tracked until the object is no longer located in the environment by;

assigning the object to at least one bucket defined within the scanned zone by the at least one sensing device; and

using at least one of subsequent sensor data and dead reckoning to re-assign the object to adjacent buckets and to determine an updated lateral distance that the object is from the reference coordinate as the vehicle moves; and

wherein the controller automatically implements a steer correction maneuver if a tracked object enters a steer away zone defined within the environment.

13. The method of claim 12, wherein the reference coordinate is a central axis of the vehicle.

14. The method of claim 12, wherein the environment is defined by:

a front edge that is displaced a predefined distance from front of the vehicle;

a rear edge that is located at a predetermined location associated with the vehicle;

a left edge that is displaced a predefined distance from a central axis of the vehicle; and

a right edge that is displaced a predefined distance from the central axis of the vehicle.

15. The method of claim 14, wherein the environment comprises:

the scanned zone, which extends;

in an axial direction rearwardly from the front edge of the environment to a predetermined axial location, wherein the axial direction is parallel to the central axis of the vehicle; and

in the lateral direction from a left predetermined location to a right predetermined location, the left predetermined location being between the left side of the truck and the left edge of the environment and the right predetermined location being between the right side of the truck and the right edge of the environment; and

a history zone that includes;

a first portion that extends laterally from the scanned zone to the left edge of the environment and extends laterally from the scanned zone to the right edge of the environment; and

a second portion that extends rearwardly from the scanned zone to the rear edge of the environment.

16. The method of claim 15, wherein the at least one sensing device scans for objects located in the scanning zone and does not scan for objects in the history zone.

17. The method of claim 16, wherein:

objects located in the scanning zone are tracked using the sensor data from the at least one sensing device and dead reckoning; and

once objects that have been detected by the at least one sensing device exit the scanned zone and enter the history zone, the objects are tracked using only dead reckoning.

18. The method of claim 17, wherein the scanned zone comprises a plurality of scan zones, each scan zone comprises a plurality of buckets, the buckets located adjacent to one another in the axial direction.

19. The method of claim 18, wherein the history zone comprises a plurality of buckets located adjacent to one another in the axial direction such that objects being tracked in the history zone during movement of the vehicle are re-assigned to adjacent buckets using dead reckoning so as to update the axial distance of the object relative to the vehicle.

20. The method of claim 12, wherein the environment defines a plurality of action zones that result in the controller implementing different steer maneuvers for each action zone, such that, depending on the action zone that a tracked object enters, the controller automatically implements a steer maneuver corresponding to the entered action zone.

21. A method for a materials handling vehicle to automatically implement a steer maneuver comprising:

receiving sensor data from at least one sensing device by a controller on a materials handling vehicle;

detecting that a selected object is in an environment proximate the vehicle; and

performing a steer maneuver by steering the vehicle such that the vehicle is substantially maintained at a desired distance from the selected object.

22. The method of claim 21, wherein performing a steer maneuver comprises steering the vehicle such that the selected object is at least partially maintained in a hug zone defined within the environment.

23. The method of claim 22, wherein performing a steer maneuver further comprises steering the vehicle such that at least a portion of the selected object is substantially maintained on a hug line associated with the hug zone.

24. The method of claim 23, wherein:

if a laterally innermost portion of the selected object is located laterally between the hug line and the vehicle, the vehicle is automatically steered away from the selected objected until the laterally innermost portion of the selected object is located on the hug line, at which point the vehicle is automatically steered to a desired heading; and

if the laterally innermost portion of the selected object is located laterally on the other side of the hug line than the vehicle, the vehicle is automatically steered toward the selected objected until the laterally innermost portion of the selected object is located on the hug line, at which point the vehicle is automatically steered to the desired heading.

25. The method of claim 24, wherein the desired heading is substantially in the axial direction.

26. The method of claim 22, wherein the hug zone extends in an axial direction that is parallel to a central axis of the vehicle and the hug zone is laterally displaced from a side of the vehicle.

27. The method of claim 21, wherein the environment comprises first and second hug zones, the first hug zone displaced laterally from the left side of the vehicle and the second hug zone displaced from the right side of the vehicle.

28. The method of claim 27, wherein the environment further comprises:

first and second stop zones laterally inwardly from the respective first and second hug zones, wherein if an object is detected in a stop zone, the vehicle is caused to initiate a braking operation;

first and second no steer zones laterally outwardly from the respective stop zones, wherein if an object is detected in at least a portion of a no steer zone the vehicle is not permitted to turn toward the no steer zone in which the object was detected; and

first and second steer zones laterally between the respective no steer zones and the respective hug zones, wherein if an object is detected in at least a portion of a steer zone the vehicle is permitted to turn toward the steer zone in which the object was detected.

29. The method of claim 28, wherein the selected object is the first object that is detected in at least one of the steer zones and the no steer zones.

30. The method of claim 27, wherein the controller is programmable to only perform a steer maneuver if an object is detected in a select one of the first and second hug zones.

31. The method of claim 21, wherein detecting that a selected object is in an environment proximate the vehicle comprises detecting that the selected object is in a scanned zone of the environment, wherein the scanned zone is scanned by the at least one sensing device.

32. The method of claim 21, wherein the selected object is an object that is determined to be the closest object to the vehicle within the environment, as measured in a lateral direction that is perpendicular to a central axis of the vehicle.

33. The method of claim 21, wherein the selected object is the first object that is detected in a scanned zone defined in the environment, wherein the scanned zone is scanned by the at least one sensing device.

34. The method of claim 21, wherein the selected object comprises one of a rack and a stacked product face having a generally axially extending edge portion such that the vehicle is substantially maintained at a desired distance from the edge portion of the rack or stacked product face.